A spectrum is a basis for wireless communication. Currently, for using of a spectrum, there is a design that allows a device in a Long Term Evolution (LTE) system and a device in a non-LTE system (for example, a Wireless Fidelity (Wireless Fidelity, WiFi) device) to jointly use an unauthorized or unlicensed (unlicensed) spectrum. Specifically, the LTE system may use the unlicensed spectrum independently or in a form of a secondary cell configuration. However, a problem urgently to be resolved is to seek a data transmission method that can ensure normal data communication between LTE devices while using the unlicensed spectrum efficiently.